The magnetostriction and dynamic magnetomechanical properties of the directionally solidified Tb0.33Dy0.67Fey/ Epoxy composite were investigated as a function of volume fraction of RFe2 under a magnetic field. This composite was fabricated by infiltrating epoxy after extracting a eutectic phase of the directionally solidified Tb0.33Dy0.67Fey. It was found that the magnetostriction of the composite is higher than that of the as-grown specimens, and the maximum magnetostrictive strain of the sample, which has a volume fraction of 0.72, showed about 1000 ppm at H-3 = 80 kA/m and an optimum preload of 8 MPa. Furthermore, the dynamic magnetomechanical properties of the composite Tb0.33Dy0.67Fey, which is the sensitivity of the strain to the applied field, increased by about two times that of as-grown samples.